#include <vector>
#include <queue>
#include <stdio.h>
using namespace std;
vector< vector<int> > graph;
vector<int> dijkstra(int V, int src)
{
vector<int> dist(V,0x7fffffff);
dist[src] = 0;
priority_queue<pair<int,int> > myqueue;
myqueue.push(make_pair(0,src));
while(!myqueue.empty())
{
int cost = -myqueue.top().first;
int here = myqueue.top().second;
myqueue.pop();
if(cost > dist[here])
{
continue;
}
for(int i=0;i<graph[here].size();i++)
{
int there = graph[here][i];
int nextDist = cost + 1;
if(dist[there] > nextDist)
{
dist[there] = nextDist;
myqueue.push(make_pair(-nextDist,there));
}
}
}
return dist;
}
int main()
{
int N,M;
scanf("%d%d",&N,&M);
if(M==0)
{
if(N==1)
{
printf("0\n");
}
else
{
printf("-1\n");
}
}
else
{
graph.resize(N);
for(int i=0;i<M;i++)
{
int f,t;
scanf("%d%d",&f,&t);
f-=1;t-=1;
graph[f].push_back(t);
}
vector<int> k = dijkstra(N,0);
if(k[N-1] == 0x7fffffff)
{
printf("-1\n");
}
else
{
printf("%d\n",k[N-1]);
}
}
return 0;
}
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
0 ms |
1240 KB |
Output is correct |
2 |
Correct |
0 ms |
1240 KB |
Output is correct |
3 |
Correct |
0 ms |
1240 KB |
Output is correct |
4 |
Correct |
0 ms |
1240 KB |
Output is correct |
5 |
Correct |
0 ms |
1240 KB |
Output is correct |
6 |
Correct |
0 ms |
1240 KB |
Output is correct |
7 |
Correct |
0 ms |
1240 KB |
Output is correct |
8 |
Correct |
0 ms |
1240 KB |
Output is correct |
9 |
Correct |
0 ms |
1240 KB |
Output is correct |
10 |
Correct |
16 ms |
1768 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
0 ms |
1240 KB |
Output is correct |
2 |
Correct |
40 ms |
7012 KB |
Output is correct |
3 |
Correct |
52 ms |
7012 KB |
Output is correct |
4 |
Correct |
40 ms |
7012 KB |
Output is correct |
5 |
Correct |
52 ms |
7012 KB |
Output is correct |
6 |
Correct |
40 ms |
7012 KB |
Output is correct |
7 |
Correct |
28 ms |
7012 KB |
Output is correct |
8 |
Correct |
100 ms |
7600 KB |
Output is correct |
9 |
Correct |
40 ms |
7012 KB |
Output is correct |
10 |
Correct |
84 ms |
6748 KB |
Output is correct |